Direct answer
A fake Cartier Rotonde 42mm is a counterfeit watch built to copy the Rotonde de Cartier case at 42 mm. Prices run from about $120 for a quartz model to $800 for a replica with a clone chronograph movement. Genuine Rotonde de Cartier 42 mm references sell new between about $7,000 and $45,000. No counterfeit carries a Cartier caliber. Cartier does not sell movements or parts to third parties.
Case size and shape
The genuine case is round and measures 42 mm across, crown excluded. Thickness on chronograph versions runs 12 mm to 13 mm. Lug width is 20 mm or 22 mm, depending on the reference. Some replica cases run 0.5 mm to 1 mm wider because the factory reuses a stock case. Use calipers for a comparison.
Genuine Rotonde cases come in steel, 18k pink gold, or 18k white gold. Gold replicas use plating over brass or steel. Plating thickness runs 3 to 5 microns. A solid gold case weighs far more than a plated one of the same size.
Movement
Cartier fits in-house calibers in the Rotonde line. The 1904-CH MC drives the chronographs. The 1904-FU MC drives the dual time models. Replicas use four sources: Chinese quartz, the Seagull ST19 hand-wound chronograph, a Miyota automatic, or a cloned ETA 7750.
Chronograph case backs have a sapphire window. Look at the balance wheel. Cartier chronograph calibers beat at 28,800 vibrations per hour. The ST19 beats at 21,600. Count the ticks in one second: 8 for 28,800, 6 for 21,600.
Dial, hands, crown
Genuine dials carry a stamped guilloche pattern. Roman numerals print with sharp edges. Replica printing bleeds at the edges under a loupe. Genuine blued-steel hands are heat treated, so they shift color as the light angle changes. Painted blue hands stay flat.
The crown cabochon is a synthetic spinel on genuine watches. Most replicas use glass or plastic. A spinel shows a sharp facet line. Glass looks cloudy at the edge.
Price bands
- $120 to $250: quartz movement, mineral crystal, plated case.
- $250 to $500: Miyota or Seagull automatic, sapphire crystal, better case finish.
- $500 to $900: clone 7750, case dimensions closer to genuine, sapphire front and back.
Above $900 the price passes the value of the parts. No replica maker publishes production numbers, so total output is unknown.
Legal note
Importing counterfeit goods into the United States violates 19 U.S.C. § 1526. CBP seizes shipments and destroys the goods. Selling a counterfeit as genuine is trademark infringement and fraud. Buying one for personal use is not a criminal charge in most states, but the watch can be seized with no refund.
What cannot be verified
No public data lists how many fake Rotonde 42mm watches exist. Factory names in the replica market change often. Any claim about a single best version is marketing.